The Tao of Testing

By: Fred Brooks

Fred Brooks says that a third of IT development time and effort should be spent in testing. In any major software development project, with many people working on the coding, testing is essential to make sure that the system performs as the requirements say it should.

However, even if you're a developer team of one, you still have an interest in ensuring that your work has proper Quality Assurance (QA) documentation for three main reasons:

1. Your future business depends entirely on your professional reputation - good clients will always look for a reputation for delivering their requirements. Anything which enhances that reputation is A Good Thing.
2. Once the system is handed over to the client, you will then have an audit trail of testing, documenting that the system is working. If it later fails, you have a backup to safeguard you against potential legal and reputational action from a panicking client.
3. If you want to feel self-interested about this (and most of us do at some point), remember that the client should pay for all of this testing - it's all chargeable time, which will result in the client getting a better system at the end of it.


So what do you have to do?

* Use Test Scripts
* Perform Tests
o Usability Testing
o Unit Testing
o System Testing
o Integration Testing
o Volume Testing
o Regression Testing
o User Acceptance Testing (UAT)
* Report and Fix Errors


Test Scripts

Testing is a systematic discipline. You need to ensure that you test every piece of functionality against its specification, and that tests repeated after a bug has been fixed are the same as the test which highlighted the bug in the first place.

The best way to ensure that there are no gaps in your test programme is to produce a test script. This will allow you to check that no area of functionality slips through the net, either at design stage, or while the tests are being performed.

Your script should outline the steps which testers will follow, and list the expected results of each test. The detail you go into will depend on the time and budget available for testing.

A sensible way of distributing the scripts is electronically - often as a word processing document. This will allow testers to record any errors which occur together with the tests which brought them out. You should archive the documents in read only format with the rest of the project documentation. To be on the safe side, the testers should print and sign the sheets, and again, you'll store these with the documentation.

Types of Testing

Usability Testing

Usability testing should happen before a single element of the user interface (including information architecture) is fixed. Performing usability tests at this stage will allow you to change the interface reasonably quickly and cheaply - backing out an interface once it is coded is always going to be difficult.

The best way to perform usability testing at this stage is to build a prototype of your proposed interface, and test that. Feedback from the testers will allow you to quickly amend your prototype and go through another iteration.

Research shows that you only need to use five testers to perform the usability tests, and find 85% of the usability issues in each iteration. After a few iterations, you're unlikely to have substantive issues left. Unit Testing

Typically, a system contains a number of pieces such as

* 'the bit which displays the product'
* 'the bit which puts the product into the shopping cart'
* 'the bit which which verifies the credit card and takes the payment'


and so on. Each of these is a unit, and you need to make sure that each unit produces the appropriate output for the input you give it, including sensible error trapping. A reasonably common (but by no means the only) way of doing this might be at a command-line, as this bypasses possible errors introduced by the web server process itself. All you are doing is checking that the basic code does what it says on the tin.

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